They had to be fully autonomous, because they were situated hundreds and hundreds miles aways from any populated areas. After reviewing different ideas on how to make them work for a years without service and any external power supply, Soviet engineers decided to implement atomic energy to power up those structures. So, special lightweight small atomic reactors were produced in limited series to be delivered to the Polar Circle lands and to be installed on the lighthouses.
RussianFilter: Historical Chronicles with Nikolai Svanidze is an ongoing Russian television documentary series which, starting with 1901, picks out one person per year, every year, of the 100 years of the 20th century in Russia. It's entirely in Russian, of course, but for them as speaks it, it's one fascinating perspective on Russian history, with excellent narration, copious detail, and fascinating interconnections of events, people and places. All of the episodes that are available through Google Video and various other sources, and [more inside]